Method and apparatus for exchanging energy and/or mass

ABSTRACT

A regenerative energy and/or mass exchange assembly is provided. The regenerative assembly comprises: an exchange media; a first flow path to pass a fluid stream through the exchange media; at least a second flow path to pass a further fluid stream through the exchange media; and at least one fluid stream diverter to divert the different flow paths to pass the respective fluid streams through different regions of the exchange media. A method for operating the regererative assembly is also provided.

FIELD OF THE INVENTION

[0001] The present invention relates generally to a method and apparatusfor exchanging energy and mass between at least two fluid streams.

BACKGROUND OF THE INVENTION

[0002] A conventional regenerative device that exchanges sensible heat,latent heat, and moisture between two streams of fluids can bemanufactured in the form of a wheel, and can be referred to as anenthalpy wheel, an energy wheel, or a heat exchange wheel (hereinafter‘enthalpy wheel’). Conventional enthalpy wheels are illustrated in U.S.Pat. Nos. 4,093,435, 4,924,934 and 6,155,334.

[0003] A conventional enthalpy wheel typically rotates on a shaft atfairly low speeds, for example, no more than about 40 r.p.m. Theenthalpy wheel typically has a housing containing a matrix of media(capable of absorbing sensible heat) that is coated with a desiccantmaterial (capable of absorbing moisture and thus latent as well assensible heat). The media can be made of alternate sheets of flat andcorrugated paper whose open-ended corrugations provide a multitude ofparallel passages through the wheel in an axial direction. Thisarrangement of the corrugations facilitates the flow of fluids throughthe enthalpy wheel. The housing together with the media is generallyrotated about the shaft by, for example, a motor.

[0004] Two fluid streams, for example, a first humidified and heated airstream and a second dry and cool air stream, can enter the enthalpywheel along the axial direction. The first air stream flows through theenthalpy wheel from one side into an area of the media where thehumidity and heat in the air stream is absorbed and retained by themedia. The second air stream flows through the enthalpy wheel, generallythrough the opposite side from the first air stream, and into an area ofthe media that is usually in symmetrical relation to the area where thefirst stream entered the housing. As the enthalpy wheel rotates aboutits axis, the area of the media that has retained and absorbed thehumidity and heat from the first air stream rotates to where the secondair stream flows through the housing to transfer humidity and heat tothe dry cool air of the second stream.

SUMMARY OF THE INVENTION

[0005] In accordance with the present invention there is provided aregenerative energy and/or mass exchange assembly comprising an exchangemedia, a first flow path to pass a fluid stream through the exchangemedia, at least a second flow path to pass a further fluid streamthrough the exchange media, and at least one fluid stream diverter todivert the different flow paths to pass the respective fluid streamsthrough different regions of the exchange media.

[0006] In one embodiment, the exchange assembly further comprises atleast one housing connected to one end of the exchange media and whereinthe flow paths are provided in the housing.

[0007] In another embodiment, the fluid stream diverter is provided inthe housing.

[0008] In another embodiment, the housing and the fluid stream divertercooperate to form the flow paths.

[0009] In another embodiment, the fluid stream diverter is rotatablymounted within the housing.

[0010] In another embodiment, the exchange media is housed in aplurality of cavities that are separated from one another in crosssection and extend in parallel along the direction of fluid stream flow.

[0011] In another embodiment, the fluid stream diverter rotates to passthe different fluid streams through the exchange media.

[0012] In another embodiment, the fluid stream diverter rotates to passthe different fluid streams through different cavities of the exchangemedia.

[0013] In another embodiment, the exchange assembly further comprises ashaft that extends through the exchange media, the at least one housingconnected to one end of the exchange media, and the fluid streamdiverter rotatably mounted within the housing.

[0014] In another embodiment, the fluid stream diverter has a radialextent that is generally less than the radial extent of the exchangemedia.

[0015] In another embodiment, the at least one housing connected to oneend of the exchange media comprises a connection portion and adispersion portion which are in fluid communication with each other.

[0016] In another embodiment, the connection portion has at least twoports adapted to connect to external fluid stream sources.

[0017] In another embodiment, the dispersion portion has an open endthat is in fluid communication with the exchange media.

[0018] In another embodiment, the connection portion has a radial extentthat is generally less than the radial extent of the dispersion portion.

[0019] In another embodiment, the fluid stream diverter is substantiallydisposed within the connection portion.

[0020] In another embodiment, the fluid stream diverter has a radialextent that is substantially equal to the radial extent of an inner wallof the connection portion.

[0021] In another embodiment, the dispersion portion comprises aplurality of chambers that are separated from one another.

[0022] In another embodiment, the plurality of cavities that house theexchange media are disposed within a central housing.

[0023] In another embodiment, each cavity is thermally insulated fromadjacent cavities.

[0024] In another embodiment, the plurality of cavities that house theexchange media are positioned in correspondence to the chambers of thedispersion portion.

[0025] In another embodiment, the cavities and the chambers aresubstantially equal in cross section and substantially evenly spacedabout the axial direction.

[0026] In another embodiment, the number of chambers is three, and thenumber of cavities is three.

[0027] In another embodiment, the number of chambers is five, and thenumber of cavities is five.

[0028] In another embodiment, the fluid stream diverter comprises insequence along the axial direction a first segment, a first reduceddiameter portion, a second segment, a second reduced diameter portion,and a third segment; an inner bore defining an inner space within thefluid stream diverter; a first passage extending from a first port inthe outer wall of the second reduced diameter portion through the innerspace and then to a second port on the outer wall of the first segment;a second passage extending from a third port on the end wall of thefirst segment adjacent to the first reduced diameter portion to a fourthport on the outer wall of the first segment; and wherein the said firstand second passages are isolated from each other.

[0029] In another embodiment, a sealing means is provided between thefluid stream diverter and the connection portion.

[0030] In another embodiment, the sealing means is provided between eachof the first, second, and third segment, of the fluid stream diverterand the inner wall of the connection portion.

[0031] In another embodiment, the connection portion has an open end anda closing means which closes the open end.

[0032] In another embodiment, the exchange assembly further comprisessnap-connection means provided between the central housing and thehousing connected to one end of the exchange media.

[0033] In another embodiment, the assembly has a first end housing and asecond end housing disposed on either end of the exchange media.

[0034] In another embodiment, a first fluid stream diverter is disposedin the first end housing and a second fluid stream diverter is disposedwithin the second end housing.

[0035] In another embodiment, the plurality of chambers of thedispersion portion of the first end housing is in substantial axialalignment with the corresponding plurality of chambers of the dispersionportion of the second end housing.

[0036] In another embodiment, the first and second fluid streamdiverters are disposed correspondingly in the respective end housingsand rotate in phase during operation.

[0037] In accordance with the present invention, there is provided amethod of exchanging energy and/or mass between at least two fluidstreams, the method comprising:

[0038] (a) passing at least two fluid streams through different regionsof an exchange media; and

[0039] (b) changing the flow paths of the fluid streams to the exchangemedia so that at least one of the fluid streams is passed through aregion of the exchange media that a different fluid stream had passedthrough.

[0040] In one embodiment, each flow path is changed by a fluid streamdiverter.

[0041] In another embodiment, the fluid stream diverter is provided in ahousing connected to one end of the exchange media.

[0042] In another embodiment, the housing and the fluid stream divertercooperate to form the flow paths.

[0043] In another embodiment, the fluid stream diverter is rotatablymounted within the housing.

[0044] In another embodiment, the exchange media is housed in aplurality of cavities that are separated from one another in crosssection and extend in parallel along the direction of fluid stream flow.

[0045] In another embodiment, the fluid stream diverter rotates to passthe different fluid streams through the exchange media.

[0046] In another embodiment, the fluid stream diverter rotates to passthe different fluid streams through different cavities of the exchangemedia.

[0047] In another embodiment, step (a) includes passing the fluidstreams through different regions of an exchange media in a concurrentdirection.

[0048] In another embodiment, step (a) includes passing the fluidstreams through different regions of an exchange media in acounter-current direction.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0049] For a better understanding of the present invention, and to showmore clearly how it may be carried into effect, reference will now bemade, by way of example, to the accompanying drawings, which show apreferred embodiment of the present invention in which:

[0050]FIG. 1a shows a perspective view of a conventional enthalpy wheel;

[0051]FIG. 1b shows a perspective view of an exchange media used in aconventional enthalpy wheel;

[0052]FIG. 2a shows a longitudinal sectional view of an enthalpy wheelassembly according to the present invention;

[0053]FIG. 2b shows an enlarged view of one end of an enthalpy wheelassembly according to the present invention;

[0054]FIG. 3a shows a plan view of a central housing accordingly to thepresent invention;

[0055]FIG. 3b shows a longitudinal sectional view of a central housingaccording to the present invention taken along the lines A-A of FIG. 3a;

[0056]FIG. 4a shows a perspective view of a first example of an endhousing according to the present invention;

[0057]FIG. 4b shows another perspective view of a first example of anend housing according to the present invention;

[0058]FIG. 4c shows a longitudinal sectional view of a first example ofan end housing according to the present invention;

[0059]FIG. 4d shows a perspective sectional view of a first example ofan end housing according to the present invention;

[0060]FIG. 5a shows a perspective view of a fluid stream diverteraccording to the present invention;

[0061]FIG. 5b shows a longitudinal sectional view of a fluid streamdiverter according to the present invention;

[0062]FIG. 5c shows a perspective sectional view of a fluid streamdiverter according to the present invention;

[0063]FIG. 5d shows another perspective view of a fluid stream diverteraccording to the present invention;

[0064]FIG. 6 shows a perspective view of a shaft according to thepresent invention;

[0065]FIG. 7a shows a perspective view of a first example of amulti-cavity media support according to the present invention;

[0066]FIG. 7b shows a perspective sectional view of a first example of amulti-cavity media support according to the present invention;

[0067]FIG. 8a shows a perspective view of a end housing according to thepresent invention with snap connection means provided thereon;

[0068]FIG. 8b shows another perspective view of a end housing accordingto the present invention with snap connection means provided thereon;

[0069]FIG. 9a shows a plan view of a central housing according to thepresent invention with snap connection means provided thereon;

[0070]FIG. 9b shows a side elevational view of a central housingaccording to the present invention with snap connection means providedthereon;

[0071]FIG. 10 shows another longitudinal sectional view of an enthalpywheel assembly according to the present invention; and

[0072]FIG. 11 shows a cross-sectional view taken along the line A-A ofFIG. 2a, illustrating the relationship between the size of the slots inthe fluid stream diverter and the openings in the end housing;

[0073]FIG. 12 shows another longitudinal sectional view of an enthalpywheel assembly according to the present invention.

[0074]FIG. 13 shows a perspective view of a second example of an endhousing and a multi-cavity media support according to the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0075] A conventional enthalpy wheel 50 is illustrated in FIG. 1a.Enthalpy wheel 50 rotates on a shaft 102, at fairly low speeds, forexample, no more than about 40 r.p.m. The enthalpy wheel 50 typicallyhas a housing 101 containing a matrix of media 103 (capable of absorbingsensible heat) that is coated with a desiccant material (capable ofabsorbing moisture and thus latent as well as sensible heat). As shownin FIG. 1b, the media 103 can be made of alternate sheets of flat andcorrugated paper whose open-ended corrugations provide a multitude ofparallel passages through the wheel in an axial direction. Thisarrangement of the corrugations facilitates the flow of fluids throughthe enthalpy wheel 50. The housing 101 together with the media 103 isgenerally rotated about the shaft 102 by, for example, a motor 104. Agroove 105 can be provided on the circumference of the housing 101 sothat a belt 106 can be placed within the groove 105 to transmit thedriving force from the motor 104 to rotate the housing 101 of theenthalpy wheel 50. A cassette housing (not shown) can enclose theenthalpy wheel 50, and be fluidly connected to gas ducts (not shown).

[0076] Two fluid streams, for example, a first humidified and heated airstream 11 and a second dry and cool air stream 21, can enter theenthalpy wheel 50 along the axial direction. The first air stream 11flows through the enthalpy wheel 50 from one side into an area of themedia 103—indicated at 15—where the humidity and heat in the first airstream 11 is absorbed and retained by the media 103. The second airstream 21 flows through the enthalpy wheel 50, generally through theopposite side from the first air stream 11, and into an area of themedia 103—indicated at 25—that is usually in symmetrical relation to thearea where the first stream 11 entered the media 103. As the housing 101of the enthalpy wheel 50 rotates about its axis, the area of the media103 that has retained and absorbed the humidity and heat from the firstair stream 11 rotates to where the second air stream 21 flows throughthe media 103 transferring humidity and heat to the dry cool air of thesecond stream 21.

[0077]FIG. 2a shows a longitudinal sectional view of an enthalpy wheelassembly 100 of the present invention. By way of example, the embodimentdisclosed will refer to an exchange of heat and humidity between two gasstreams such as, for example, in a ventilation or air conditioningsystem. However, it is understood that the enthalpy wheel 100 can beused to exchange energy and/or mass between more than two fluid streams.More specifically, the enthalpy wheel assembly 100 might also haveapplicability to other uses, such as, but are not limited to, gaspurification, gas enrichment, valuable component recovery from gasmixtures, and selective mass transfer between two gas streams.

[0078] Referring to FIG. 2a, the enthalpy wheel assembly 100 comprises acentral housing 120, a first end housing 140 and a second end housing140′. For the embodiment illustrated in FIG. 2a, the components in thefirst end housing 140 are identical to those in the second end housing140′. Accordingly, the numbers relating to the second end housing 140′are denoted with a suffix ′. The central housing 120 is preferablycylindrical in shape and contains an exchange media 110. A suitableexchange media comprises random oriented fiber based carbon papercommercially available from E-TEK, or carbon cloth commerciallyavailable from W. L. Gore. The media 110 has two end surfaces 112, 112′.The two end housings 140, 140′ are placed at the opposite open ends ofthe central housing 120. A shaft 180 extends throughout the threehousings 120, 140, 140′, preferably along the center of the annularsection of those housings. Further, a fluid stream diverter 200 isfitted into the first end housing 140 about shaft 180, as willhereinafter be described. Furthermore, the fluid stream diverter 200 andthe end housing 140 in the embodiment disclosed cooperate with oneanother to form at least two flow paths to the exchange media 110 forthe external gas streams. Moreover, the second end housing 140′ can alsobe provided with a fluid stream diverter 200′.

[0079] As shown in FIGS. 3a and 3 b, the central housing 120 of theenthalpy wheel assembly 100 has enlarged inner diameter portions 121 and123 at each end thereof. The enlarged diameter portions 121 and 123 areadapted to connect the first and second end housings 140, 140′ to thecentral housing 120.

[0080]FIGS. 4a-4 d show various perspective and sectional views of afirst example of an end housing. It is understood that although thenumbers in FIG. 4 correspond to the first end housing 140, they areequally applicable to the second end housing 140′.

[0081] Referring to FIG. 4a, the first end housing 140 has a connectionportion 141 and a dispersion portion 142, which are in fluidcommunication with each other. The connection portion 141 has an outerwall 153 and an inner wall 152. Inner wall 152 defines an inner chamber160 that can be cylindrical in shape. The outer wall 153 of theconnection portion 141 can define a plane portion 154 having two gasports 143, 144 provided thereon. The gas ports 143, 144 are in fluidcommunication with the inner chamber 160 of the connection portion 141.The open end of the connection portion 141 is closeable by a closingmeans 500 (see FIG. 2a), such as a threaded cap or the like. Referringto FIG. 4d a number of annular grooves 400 are provided in parallelrelation on the inner wall 152 of the connection portion 141, toaccommodate a sealing means, such as an O-ring (not illustrated).

[0082]FIGS. 4a and 4 b show an end wall 158 of the dispersion portion142 extending radially from the connection portion 141, and a portion157 extending axially from end wall 158. The axially extending portion157 can be cylindrical in shape and have a reduced outer diameterportion 147 adapted to fit into the enlarged inner diameter portion 121of the central housing 120 as shown in FIG. 2a. An O-ring groove 155 canbe provided on the reduced diameter portion 147 for sealing between thecentral housing 120 and the first end housing 140.

[0083] A journal 145 is provided at the center of the open end of thedispersion portion 142. A plurality of chamber dividers 151 extendsradially from the journal 145 towards the outer wall of the dispersionportion 142 to define a plurality of chambers 150. The journal 145 has aportion 146 that extends axially towards the connection portion 141.Further, portion 146 is spaced from the inner end wall 158 of thedispersion portion 142 forming a plurality of partially circularopenings 156 within each chamber 150 of the dispersion portion 142.Openings 156 provide a plurality of gas flow paths into the plurality ofchambers 150 from the inner chamber 160 of connection portion 141. Thejournal 145 has a hub 149 that supports the shaft 180.

[0084] At least one annular groove 148 can be provided on an inner wall161 of the axially extending portion 146 for sealing, for example, byusing an O-ring (not illustrated). The inner wall 161 of the axiallyextending portion 146 can have roughly the same diameter as the innerchamber 160 of the connection portion 141. The dispersion portion 142and the journal 145 have a common end face 159.

[0085]FIG. 2a shows the fluid stream diverter 200 fitted into the firstend housing 140. FIGS. 5a, 5 b, and 5 c show the detailed structure ofthe fluid stream diverter 200. The fluid stream diverter 200 has aplurality of reduced diameter portions. Specifically, in the preferredembodiment, the fluid stream diverter 200 has a first segment 220, asecond segment 240, and a third segment 260, as well as a first reduceddiameter portion 230 and a second reduced diameter portion 250. Thesegments 220, 240 and 260 can have the same diameter. Likewise, thereduced diameter portions 230, 250 can have the same reduced diameter.Within an end surface 210 of the fluid stream diverter 200 a slot 211 isprovided. Preferably, slot 211 is arc shaped, and has a smaller radiusthan the end surface 210 of the first segment 220. The slot 211 extendsaxially throughout the first segment 220. On the outer wall 221 of thefirst segment 220 two slots can be provided, namely slots 212 and 213.Slot 211 is in fluid communication with slot 212.

[0086] The fluid stream diverter 200 has an inner bore 214 extendingaxially throughout the length thereof. The inner bore 214 extends to aposition adjacent to the end surface 210, at which point it has areduced diameter portion 215 for supporting the shaft 180. The innerbore 214 is isolated from slots 211 and 212. Slot 213 is in fluidcommunication with inner bore 214.

[0087] The second reduced diameter portion 250 is provided with aplurality of holes that penetrate this portion, namely, a plurality ofgas dispersion holes 251 and pinholes 253. As shown in FIG. 2b, at leastone of the pinholes 253 can be used to accommodate a pin 350 to fix thefluid stream diverter 200 to the shaft 180 so that the fluid streamdiverter 200 rotates with the shaft to disperse the gas streams, as willhereinafter be described.

[0088] On an end surface 270 of the third segment 260, a number of screwholes 271 are provided. These screw holes 271 are used to accommodatescrews to enable the fluid stream diverter 200 to be removed from thefirst end housing 140 when the enthalpy wheel 100 is disassembled. Fluidstream diverters 200 and 200′ are respectively fitted into the innerspaces 160, 160′ of the first and second end housings 140 and 140′. Theshaft 180 passes through the respective reduced diameter portions 215,215′ of the fluid stream diverters 200 and 200′ and the fluid streamdiverters are fixed to the shaft 180 using respective pins 350, 350′.During operation, the fluid stream diverters 200, 200′ are continuouslyrotating with the shaft 180.

[0089] Referring to FIG. 2a, a heat and mass exchange media 110 isdisposed within the central housing 120. The media has an inner hole 111extending axially therethrough to rotatably receive the shaft 180. Inoperation, the shaft is driven by a motor (not shown). This arrangementallows the fluid stream diverters 200 and 200′ within the first andsecond end housings 140 and 140′ to rotate in phase with the shaft 180without turning the media 110 therein. As described above, each of thefirst and second end housings 140 and 140′ has a reduced diameterportion 147 adapted to fit into the enlarged diameter portion 121, 123of the central housing 120. Preferably, sealing means 122, for exampleO-rings, are provided to prevent leakage of any gas from the gasstreams. Preferably, the media 110 and the first and second end housings140 and 140′ are dimensioned such that the end surfaces 159, 159′ of thejournals 145, 145′ are adjacent to, but not in contact with, the endsurfaces 112, 112′ of the media, as shown in FIG. 2a.

[0090] Shaft 180 (see FIG. 6) is provided with pinholes 183 and 183′. Ascan be seen on the left side of FIG. 2a, the fluid stream diverter 200is fixed with respect to the shaft by means of a pin 350 that fits intothe pinhole 253 of the fluid stream diverter 200 and one of the pinholes183 and 183′ on the shaft 180. Therefore, the fluid stream diverter 200rotates in the same phase as the shaft 180.

[0091] As the diameter of the inner bore 214 of the fluid streamdiverter is greater than the outer diameter of the shaft 180, a gas flowpath is formed within the fluid stream diverter 200. The inner chamber160 of the connection portion 141 preferably has substantially the samediameter as that of the outer wall 221 of the fluid stream diverter 200,which, as seen in FIGS. 5a and 5 b is the diameter of the first, secondand the third segments 220, 240, 260. The fluid stream diverter 200 ispositioned within the first housing 140 on the shaft 180 such that thesecond segment 240 of the fluid stream diverter 200 is in substantialalignment with a groove 400 provided on the inner wall 152 of theconnection portion 141 in which, for example, an O-ring (notillustrated) can be placed to provide a seal. With fluid stream diverter200 positioned within first end housing 140 as illustrated in FIG. 2b, afirst inner space 440 between the second segment 240 and third segment260 is provided that is separated from a second inner space 441 betweenthe first segment 220 and the second segment 240. Moreover, the thirdsegment 260 can be provided with an O-ring (not illustrated).

[0092] Now referring to FIGS. 5a, 5 b and 5 c, the first end housing 140and the fluid stream diverter 200 are dimensioned such that each of theslots 212, 213 of the first segment 220 of the fluid stream diverter 200are substantially in alignment with each of the plurality of openings156 located in the plurality of chambers 150 for dispersing gases whenthe fluid stream diverter 200 is disposed in the first end housing 140.Preferably, the journal 145 is provided with at least one groove 148.Since the diameter of the inner wall 161 of the journal 145 issubstantially the same as that of the inner wall 152 of the connectionportion 141, it is substantially the same as the diameter of the outerwall 221 of the first segment 220 of the fluid stream diverter 200.Sealing means, for example an O-ring (not illustrated), can be placed inthe groove 148 to provide sealing between the journal 145 and the firstsegment 220. When in assembly, two separate plates are provided for thefluid stream diverter 200, namely, a sealing plate 370 and a supportplate 380 (see FIGS. 2a and 2 b). As can best be seen in FIG. 5b, thesealing plate 370 is formed in accordance with the shape of the slot 211of the first segment 220 and has a certain thickness so that it can fitinto the slot 211 and close the slot 211 on the end surface 210. Sealingplate 370 can be fixed onto the fluid stream diverter 200 by means of,for example, welding or the like. The support plate 380 is provided witha through hole so that the shaft 180 can pass through it. The supportplate 380 has a diameter that is greater than the diameter of the innerbore 214 of the fluid stream diverter 200. The internal bore 214 of thefluid stream diverter 200 is provided with a step 272 at a positionadjacent the end face 270 so that the support plate 380 can fit into theinner bore 214 of the fluid stream diverter 200 and abut against thestep 272. Therefore, the fluid stream diverter 200 is supported aboutthe shaft 180 at two positions adjacent to the ends thereof, i.e., byreduced diameter portion 215 and by support plate 380.

[0093] Still referring to FIGS. 2a and 2 b, a closing means 500, such asa cap, is provided on the end surface of the connection portion 141 ofthe first end housing 140. The closing means 500 is fixed onto the endsurface of the connection portion 141 in a known manner, such as, forexample, a screw connection as illustrated at 501. The closing means 500supports the shaft 180 by means of a bearing 385. The shaft is alsosupported by the journal 145 by means of a bearing 375. Sealing betweenthe journal 145 and the shaft 180 can be provided by, for example, anO-ring. Therefore, the shaft 180 is supported by the first end housing140 in two locations using bearings.

[0094] As shown in FIG. 4b two gas ports 143 and 144 are provided on theplane portion 154 of the connection portion 141 of the first end housing140. The two gas ports 143 and 144 are in fluid communication with theinner chamber 160 of the connection portion 141. In the radialdirection, the gas port 143 is in fluid communication with the followingcomponents: the first inner space 440, the plurality of gas dispersionholes 251, the inner bore 214, the slot 213, and, with appropriaterotation of the fluid stream diverter 200, as will hereinafter bedescribed, the plurality of openings 156, the plurality of chambers 150,and the central housing 120. The gas port 144 is in fluid communicationwith the following components: the second inner space 441, the slot 211,the slot 212, and, with appropriate rotation of the fluid streamdiverter 200, as will hereinafter be described, the plurality ofopenings 156, the plurality of chambers 150, and the central housing120. In the same manner, the central housing 120 is in fluidcommunication with the second end housing 140′.

[0095] The first and second end housings 140, 140′ are positioned suchthat the plurality of chambers 150 of the first end housing 140 aregenerally in alignment with the chambers 150′ of the second end housing140′. Additionally, the fluid stream diverters 200 and 200′ turn inphase with each other while the enthalpy wheel assembly 100 is inoperation. That is to say, the positions of the slots 211, 212, 213 areconstantly in alignment with those of the slots 211′, 212′, 213′ in theaxial direction.

[0096] As described above, the exchange media 110 typically has amultitude of parallel fluid channels. When operating with fluid streamshaving higher pressures and/or high-pressure gradients, the fluid streamthat has a higher pressure tends to crossover the axially extendingchannels of the media 110 towards the fluid stream having a lowerpressure. This can result in poor humidity and/or heat exchange, andeven leakage of the enthalpy wheel assembly 100. Therefore, the enthalpywheel assembly 100 of the present invention preferably has amulti-cavity media support 300, as shown in FIGS. 7a and 7 b. Themulti-cavity media support 300 has an inner wall 302 and is generallycylindrical in shape, as the central housing 120, but with a smallerdiameter. The multi-cavity media support 300 has a hub 310 for the shaft180 to pass through. A plurality of cavity dividers 303 extend radiallyfrom the hub 310 towards the inner wall 302 of the multi-cavity mediasupport 300 and axially throughout the length thereof, thereby dividingthe inner space thereof into a plurality of cavities 301, correspondingto the number of the chambers 150. Moreover, the multi-cavity mediasupport 300 has an end face 304.

[0097] In operation, the multi-cavity media support 300 is fitted intothe central housing 120, and the media is then separately placed intothe plurality of cavities 301. Therefore, the media in one cavity 301 isisolated from those in adjacent cavities. Each chamber 150, 150′ withinthe first and second end housings 140 and 140′ is respectively alignedwith a corresponding cavity 301 within the multi-cavity media support300. Since the end housings 140, 140′ and the multi-cavity media support300 do not rotate, an appropriate conventional face sealing means, suchas, for example, a gasket (not shown), may be utilized to providesealing between the stationary end face 304 of the multi-cavity mediasupport 300 and stationary end faces 159 and 159′ of the first andsecond end housings 140 and 140′ respectively. As a result, differentgas stream paths are isolated from one another and stream leakage fromhigher-pressure streams to lower pressure streams across the mediamaterial is prevented by the isolating property of the multi-cavitymedia support 300 and the sealing technique mentioned above. Optionally,the material of the multi-cavity media support 300 may also be chosen tohave a thermal insulation property, so that the stream paths are furtherthermally insulated from one another, and from the wall of the centralhousing 120 and thus the environment.

[0098] Now referring to FIGS. 8a, 8 b, 9 a and 9 b, the central housing120 and the first and second end housings 140 and 140′ can be providedwith snap connection means for easily disassembling the enthalpy wheelassembly 100. On the outer walls of the first and the second endhousings 140 and 140′, a plurality of attachments 80 are provided. Onthe outer wall of the central housing 120, a number of latches 70 andhooking means 60 are provided. The hooking means 60 can be configured tohook the attachments 80 to form a snap-on connection with the latches70. The latches 70 can be gripped by hand to drive the hooking means 60to hook the attachments 80. This forms a snap-on connection that enablesthe central housing 120 and the first and second end housings 140 and140′ to be connected and disconnected with ease. This arrangementsimplifies the task of replacing the media.

[0099] The arrangement of FIG. 2a is intended to provide energy and/ormass exchange between two fluid streams. This is explained further, bythe detailed descriptions of the different modes of operation describedbelow.

[0100] For example, referring to FIG. 10, a first warm and humidifiedgas stream 10 and a second cool and dry gas stream 20 run concurrentlythrough the enthalpy wheel assembly 100, that is, the gas streams 10, 20enter through the same side of the wheel 100, and exit through the sameside of the wheel 100. The first gas stream 10 enters the enthalpy wheelassembly 100 through gas port 143, and flows into the first inner space440. From here, the first gas stream 10 flows through the plurality ofgas dispersion holes 251 located on the second reduced diameter portion250, into the inner bore 214 of the fluid stream diverter 200. Next, thefirst gas stream 10 flows along the length of the inner bore 214, andexits the fluid stream diverter 200 through slot 213. As the fluidstream diverter 200 is continuously rotating with the shaft 180, thefirst gas stream 10 flows into one of the chambers 150 via a respectiveopening 156 when the fluid stream diverter 200 rotates into a positionwhere slot 213 fluidly communicates with one of the openings 156. As thegas streams are usually conveyed by means of blowers (not illustrated),the first gas stream 10 is forced to flow along the axial direction intothe media 110 supported in one of the cavities 301 in the centralhousing 120. As previously mentioned, the media 110 in one of thecavities 301 has a plurality of axially extending channels that are notin communication with the plurality of axially extending channels in theother of the cavities in either the radial or circumferentialdirections. Therefore, the first gas stream 10 flows along the pluralityof media channels to the corresponding chamber 150′ of the second endhousing 140′. From here, the first gas stream 10 flows through opening156′ and slot 213′ respectively, and enters the inner bore 214′ of thefluid stream diverter 200′. Next, the first gas stream 10 flows alongthe length of the inner bore 214′, exits through the plurality of holes251′, passes through the first inner space 440′, exits the enthalpywheel assembly 100 through the gas port 143′, and passes into anexternal duct (not shown). As the first gas stream 10 flows across theplurality of channels in the media 110, the heat and humidity of thefirst gas stream is retained in the media 110. Since the fluid streamdiverter 200 continually rotates with the shaft 180, the first gasstream 10 flows through all the channels of the media 110 to retain heatand humidity.

[0101] A second gas stream 20 enters the enthalpy wheel assembly 100through gas port 144, and flows into the second inner space 441. It isnoted that the first inner space 440 is isolated from the second innerspace 441. From here, the second gas stream 20 passes through slots 211and 212 respectively. The second gas stream 20 then flows into one ofthe separate chambers 150 via a respective opening 156 when the fluidstream diverter 200 rotates into a position where slot 212 fluidlycommunicates with one of the openings 156. Next, the second gas stream20 flows along the plurality of media channels in one of the cavities301 of the central housing 120 to a corresponding chamber 150′ of thesecond end housing 140′. As stated above, the humidity and heat of thefirst gas stream 10 is retained in all the channels of the media in allof the cavities 301 of the central housing 120. Therefore, as the secondgas stream 20 flows along the channels heat and humidity is transferredto it. Hence, the second gas stream 20 is heated and humidified as itpasses through the media 110 to chamber 150′ of the second end housing140′. From here, the second gas stream 20 flows through opening 156′,slots 212′ and 211′ respectively, and enters the second inner space441′. Next, the second gas stream 20 exits the enthalpy wheel assembly100 through gas port 144′, and passes into an external duct (not shown).

[0102] It is noted that at any time, any one of chambers 150, mediacavities 301, and chambers 150′, will only contain either gas from thefirst stream 10 or gas from the second stream 20. The chamber dividers151 separate each chamber so that the first and second gas streams 10,20 will never mix. To ensure no mixing of the gas streams, for theembodiment illustrated, the size of the slots 212, 213 of the fluidstream diverter 200 and the size of the openings 156 are selected andoriented as follows. FIG. 11 shows the relationship between the size ofthe slots 212, 213 and the three openings 156, in case of three chambers150, and numbered in FIG. 11 as 156 a, 156 b, and 156 c. In this Figure,segments 212 a and 213 a, respectively, indicate cords corresponding tothe arc shaped slots 212 and 213. Therefore, the two ends of eachsegment 212 a, 213 a represent the two ends of each slot 212, 213,respectively. As illustrated in FIG. 11, the fluid stream diverter 200is rotating in a clockwise direction. The slots 212, 213 and theopenings 156 should be sized and oriented such that at the moment theslot 213 rotates away from chamber 150 a, to cut off fluid communicationbetween the slot 213 and the opening 156 a, the slot 212 does notfluidly communicate with the same opening 156 a. This arrangement willensure the first and second fluid streams will not mix in each chamber150.

[0103] Now referring to FIG. 12, in a second embodiment, the gas streams10, 20′ run through the enthalpy wheel 100 counter-currently, that is,the first gas stream 10 enters the wheel 100 on one side, and the secondgas stream 20′ enters the wheel 100 on the opposite side. This is thepreferred mode of operation. The first gas stream 10 follows the samegas flow path as the first embodiment described above and will not berepeated.

[0104] A second gas stream 20′ enters the enthalpy wheel assembly 100through gas port 144′ of the second end housing 160, and flows into thesecond inner space 441′. From here, the second gas stream 20′ passesthrough slots 211′ and 212′, respectively. The second gas stream 20′then flows into one of chambers 150′ via a respective opening 156′ whenthe fluid stream diverter 200′ rotates into a position where slot 212′fluidly communicates with one of the openings 156′. Next, the second gasstream 20′ flows along the plurality of media channels in one of thecavities 301 of the central housing 120 to a corresponding chamber 150of the first end housing 140. As the second gas stream 20′ flows alongthe channels heat and humidity is transferred to it as described abovefor the embodiment of FIG. 10. From here, the second gas stream 20 flowsthrough opening 156, slots 212 and 211 respectively, and enters thesecond inner space 441 of the first end housing 140. Next, the secondgas stream 30 exits the enthalpy wheel assembly 100 through gas port144, and passes into an external duct (not shown).

[0105]FIG. 13 shows a perspective view of an end housing 140 and amulti-cavity support 300 according to a second example of the presentinvention. In this example, the end housing 140 has five chamberdividers 151 that section the dispersion portion 142 into five separatechambers 150. Likewise, the multi-cavity support 300 has five cavitydividers 303 that divide the inner space of the multi-cavity support 300into five separate cavities 301 corresponding to the chambers 150 of theend housing 140. It is understood that the chambers 150 and the cavities301 are in alignment during operation and that at any time, any one ofchambers 150, media cavities 301, and chambers 150′, will only containeither gas from the first stream 10 or gas from the second stream 20.The chamber dividers 151 separate each chamber so that the first andsecond gas streams 10, 20 will never mix. The size and orientation ofthe slots 212, 213 of the fluid stream diverter 200 and the size andorientation of the openings 156 are selected depending on the actualnumber of chambers 150 and to ensure no mixing of the gas streams.

[0106] It is also understood that although in the above embodiments, thecentral housing 120, the connection portions 142, 142′, the dispersionportions 143, 143′ of the end housings 140, 140′, and the first, secondand third segments 220, 240, 260 are all described as cylindrical inshape, the actual shape may vary as required. These components may havedifferent perimetrical extents at different axial positions thereof.Therefore, the words “diameter” and “radial” as used in this disclosuredo not limit the shape of the components.

[0107] The enthalpy wheel 100 can work in many different systems sinceit has the ability to operate in two different modes, that isconcurrently and counter-currently. Moreover, the connections betweenthe central housing 120 and the end housings 140, 140′ are adapted foreasy assembly and disassembly of the enthalpy wheel 100.

[0108] Additionally, since the central housing 120 and hence the mediado not rotate during operation, the system can work with two or more gasstreams having high pressure and/or high pressure gradients. By havingthe enthalpy wheel remain stationary during operation the system can bescaled up or down for use in novel applications. Moreover, since therotary members have smaller diameters than conventional designs, theenthalpy wheel assembly of the present invention can require lessdriving force for rotation, reducing system energy loss and improvingsystem efficiency.

[0109] While the above description constitutes the preferredembodiments, it will be appreciated that the present invention issusceptible to modifications and changes without departing from the fairmeaning of the proper scope of the accompanying claims. For example, theexchange media can comprise any material that is well known in the art.Moreover, since the central housing 120 and the media 300 do not rotateduring operation, the housings of the present invention are not limitedto cylindrical shapes. The shapes of the housings 120, 140, 140′ mayinclude, but are not limited to, square, rectangular or triangular.Similarly, the fluid stream diverters 200 are not limited to the shapeas disclosed herein.

We claim:
 1. A regenerative energy and/or mass exchange assembly,comprising: (a) an exchange media; (b) a first flow path to pass a fluidstream through the exchange media; (c) at least a second flow path topass a further fluid stream through the exchange media; and (d) at leastone fluid stream diverter to divert the different flow paths to pass therespective fluid streams through different regions of the exchangemedia.
 2. An exchange assembly according to claim 1 further comprisingat least one housing connected to one end of the exchange media andwherein the flow paths are provided in the housing.
 3. An exchangeassembly according to claim 2 wherein the fluid stream diverter isprovided in the housing.
 4. An exchange assembly according to claim 3wherein the housing and the fluid stream diverter cooperate to form theflow paths.
 5. An exchange assembly according to claim 4 wherein thefluid stream diverter is rotatably mounted within the housing.
 6. Anexchange assembly according to claim 5 wherein the exchange media ishoused in a plurality of cavities that are separated from one another incross section and extend in parallel along the direction of fluid streamflow.
 7. An exchange assembly according to claim 5 wherein the fluidstream diverter rotates to pass the different fluid streams through theexchange media.
 8. An exchange assembly according to claim 6 wherein thefluid stream diverter rotates to pass the different fluid streamsthrough different cavities of the exchange media.
 9. An exchangeassembly according to claim 7 or 8 further comprising a shaft thatextends through the exchange media, the at least one housing connectedto one end of the exchange media, and the fluid stream diverterrotatably mounted within the housing.
 10. An exchange assembly accordingto claim 9 wherein the fluid stream diverter has a radial extent that isgenerally less than the radial extent of the exchange media.
 11. Anexchange assembly according to claim 10 wherein the at least one housingconnected to one end of the exchange media comprises a connectionportion and a dispersion portion which are in fluid communication witheach other.
 12. An exchange assembly according to claim 11 wherein theconnection portion has at least two ports adapted to connect to externalfluid stream sources.
 13. An exchange assembly according to claim 12wherein the dispersion portion has an open end that is in fluidcommunication with the exchange media.
 14. An exchange assemblyaccording to claim 13 wherein the connection portion has a radial extentthat is generally less than the radial extent of the dispersion portion.15. An exchange assembly according to claim 14 wherein the fluid streamdiverter is substantially disposed within the connection portion.
 16. Anexchange assembly according to claim 15 wherein the fluid streamdiverter has a radial extent that is substantially equal to the radialextent of an inner wall of the connection portion.
 17. An exchangeassembly according to claim 16 wherein the dispersion portion comprisesa plurality of chambers that are separated from one another.
 18. Anexchange assembly according to claim 17 wherein the plurality ofcavities that house the exchange media are disposed within a centralhousing.
 19. An exchange assembly according to claim 18 wherein eachcavity is thermally insulated from adjacent cavities.
 20. An exchangeassembly according to claim 19 wherein the plurality of cavities thathouse the exchange media are positioned in correspondence to thechambers of the dispersion portion.
 21. An exchange assembly accordingto claim 20 wherein the cavities and the chambers are substantiallyequal in cross section and substantially evenly spaced about the axialdirection.
 22. An exchange assembly according to claim 21, wherein thenumber of chambers is three, and the number of cavities is three.
 23. Anexchange assembly as accordingly to claim 21, wherein the number ofchambers is five, and the number of cavities is five.
 24. An exchangeassembly according to claim 22 or 23, wherein the fluid stream divertercomprises in sequence along the axial direction a first segment, a firstreduced diameter portion, a second segment, a second reduced diameterportion, and a third segment; an inner bore defining an inner spacewithin the fluid stream diverter; a first passage extending from a firstport in the outer wall of the second reduced diameter portion throughthe inner space and then to a second port on the outer wall of the firstsegment; a second passage extending from a third port on the end wall ofthe first segment adjacent to the first reduced diameter portion to afourth port on the outer wall of the first segment; and wherein the saidfirst and second passages are isolated from each other.
 25. An exchangeassembly according to claim 24 wherein sealing means is provided betweenthe fluid stream diverter and the connection portion.
 26. An exchangeassembly according to claim 25 wherein sealing means is provided betweeneach of the first, second, and third segment, of the fluid streamdiverter and the inner wall of the connection portion.
 27. An exchangeassembly according to claim 26 wherein the connection portion has anopen end and a closing means which closes the open end.
 28. An exchangeassembly according to claim 18 further comprising snap-connection meansprovided between the central housing and the housing connected to oneend of the exchange media.
 29. An exchange assembly according to claim20 wherein the assembly has a first end housing and a second end housingdisposed on either end of the exchange media.
 30. An exchange assemblyaccording to claim 29 wherein a first fluid stream diverter is disposedin the first end housing and a second fluid stream diverter is disposedwithin the second end housing.
 31. An exchange assembly according toclaim 30 wherein the plurality of chambers of the dispersion portion ofthe first end housing is in substantial axial alignment with thecorresponding plurality of chambers of the dispersion portion of thesecond end housing.
 32. An exchange assembly according to claim 31wherein the first and second fluid stream diverters are disposedcorrespondingly in the respective end housings and rotate in phaseduring operation.
 33. A method of exchanging energy and/or mass betweenat least two fluid streams, the method comprising: (a) passing at leasttwo fluid streams through different regions of an exchange media; (b)changing the flow paths of the fluid streams to the exchange media sothat at least one of the fluid streams is passed through a region of theexchange media that a different fluid stream had passed through.
 34. Amethod according to claim 33 wherein each flow path is changed by afluid stream diverter.
 35. A method according to claim 34 wherein thefluid stream diverter is provided in a housing connected to one end ofthe exchange media.
 36. A method according to claim 35 wherein thehousing and the fluid stream diverter cooperate to form the flow paths.37. A method according to claim 36 wherein the fluid stream diverter isrotatably mounted within the housing.
 38. A method according to claim 37wherein the exchange media is housed in a plurality of cavities that areseparated from one another in cross section and extend in parallel alongthe direction of fluid stream flow.
 39. A method according to claim 37wherein the fluid stream diverter rotates to pass the different fluidstreams through the exchange media.
 40. A method according to claim 37wherein the fluid stream diverter rotates to pass the different fluidstreams through different cavities of the exchange media.
 41. A methodaccording to claim 37 wherein in step (a) passing the fluid streamsthrough different regions of an exchange media is in a concurrentdirection.
 42. A method according to claim 37 wherein in step (a)passing the fluid streams through different regions of an exchange mediais in a counter-current direction.